This invention relates to a food package and to a container for forming the package. The package exhibits particular utility in the microwave cooking art.
In spite of its appeal for fast cooking of food stuffs, microwave cookery has until fairly recently been limited by the inability of microwave ovens to brown and crispen foodstuffs, such as dough products and breaded items. Although cooked, the absence of browning and crispness on the surface of a food item, or at least on a portion of its surface, does not yield the desired texture or fully cooked appearance and hence lacks appeal to many consumers. Within recent times, however, advances in microwave cooking technology have been made to at least partially overcome this problem. Namely, one or more materials are now available, often termed susceptor material, which are typically applied to a surface of a food package. Typically, the susceptor material is defined by a thin layer of a metal, such as aluminum, which has been vacuum deposited on a plastic film carrier. Such a susceptor material has the property of absorbing at least a portion of the microwave energy from the oven and transforming it into heat. By virtue of intimate thermal contact between one or more surfaces of the food product with such a susceptor material layer, browning and crisping of foodstuffs in microwave ovens can be realized.
It is accordingly now common for consumers to purchase frozen packaged food products, which can be placed in a microwave oven and cooked and browned. However, many of the existing package concepts suffer from shortcomings which limit their utility, add substantial bulk to the total package or cause the consumer to perform difficult manipulations of the food and the container. Bags and sleeves incorporating metallized plastic films as microwave susceptor materials have been considered as alternatives to existing forms of microwave food containers, but these too have had a number of shortcomings. For example, some earlier designs resulted in unacceptably long cooking times because the metallized film used as the microwave susceptor material covered the full internal area of the bag or sleeve and thus partially shielded the food from direct radiation with microwave energy. Further, such prior constructions were not well suited for food products requiring browning or crisping on only one side, or conversely, if designed for single side browning or crisping, then they were not suited for food products requiring browning and crisping one two sides. Other drawbacks included overheating and charring of paper in areas where plies of metallized film were overlapped, and the prior constructions also were not readily adaptable for food products of different sizes. Prior constructions also were nonuniform in thickness when folded flat and therefore not suitable for handling in roll form. Additionally, often there was no provision for draining or collection of liquids such as grease or water often exuded by the food during cooking and no provision was made for easy handling during placement in the microwave oven and removal from the oven at the completion of the cooking process.